Apparatus for sterilizing a liquid with focused acoustic standing waves

Abstract

Apparatus and method for sterilization of liquid includes a liquid container containing a liquid and having a piezoceramic ring that is connected to a power supply system. Power supply system supplies electric signals to the piezoceramic ring that are transformed into mechanical waves and cause vibrations in the liquid.

1. An apparatus to substantially sterilize a liquid comprising:
 at least one ring of piezoceramic material, the ring being of an arbitrary shape and length, and being attached to the inner side of a sterilization tube, which has an internal passage with non-flowing or flowing liquid; and 
 a power supply system connected to the ring and adapted to supply electric waves to the ring at a frequency estimated to be a resonance frequency of a system formed by the ring and the liquid; thereby focusing acoustic standing waves, wherein a high pressure and a cavitation column is produced in the middle of the ring. 
 
     
     
       2. The apparatus of  claim 1 , wherein the ring has dimensions of 0.05-50 mm thickness; 1-100 mm inner radius; and 1-1000 mm length; and a shape selected from the group consisting of cylindrical, convex, concave, and tapered. 
     
     
       3. The apparatus of  claim 2 , wherein said ring is coated on at least one surface by a conducting material, the conducting material being selected from a group consisting of: silver, gold, nickel, and conducting rubber. 
     
     
       4. The apparatus of  claim 3 , wherein said electric waves cause said ring to vibrate along its thickness. 
     
     
       5. The apparatus of  claim 4 , wherein the electric waves cause the ring to vibrate such that standing thickness waves are produced within the liquid. 
     
     
       6. The apparatus of  claim 3 , wherein said electric waves cause said ring to produce torsion vibrations. 
     
     
       7. The apparatus of  claim 6 , wherein the electric waves cause said ring to vibrate such that standing torsion waves are produced within the liquid. 
     
     
       8. The apparatus of  claim 3 , wherein said electric waves cause said ring to vibrate along its length. 
     
     
       9. The apparatus of  claim 8 , wherein the electric waves cause the ring to produce standing longitudinal waves within the liquid. 
     
     
       10. The apparatus of  claim 3  wherein the power supply system comprises a pulse power supplier, a MHz power supplier, an amplifier, a controller, and a sensing device, wherein the MHz power supplier is to produce electric waves in the frequency range of 0.1-20 MHz. 
     
     
       11. The apparatus of  claim 10  wherein the electric waves are in the range of 0.1-20MHz and cause thickness and torsion vibration modes in the ring. 
     
     
       12. The apparatus of  claim 3  wherein the power supply system further comprises a KHz power supplier, for producing electric waves in the range of 20-500KHz, and exciting the 1st or 2nd vibration modes. 
     
     
       13. The apparatus of  claim 12 , further comprising a mixer to mix electric waves intended to produce thickness, torsion and longitudinal vibratiojns. 
     
     
       14. The apparatus of  claim 2  comprising: a second piezoceramic ring, wherein the first and the second ring are constructed from the same or different piezo material, wherein the ring dimensions, shape and materials resulting in variable shapes of cavitation area along the ring. 
     
     
       15. A device to substantially sterilize a liquid comprising:
 a piezoceramic ring, said ring being of an arbitary shape and length, and being attached to an inner diameter of a tubular sterilization container, which has an internal passage with non-flowing or flowing liquid; and 
 a power supply system connected to said ring and adapted to supply electric waves to said ring at a frequency estimated to be a resonance frequency of a system formed by said ring and the liquid; thereby focusing acoustic standing waves, wherein a cavitation column is produced in the middle of the ring.